Considering Biodiversity In The EIA Process

What Is Biodiversity?

The Convention on Biological Diversity defines Biodiversity as the variability among living organisms from all sources including terrestrial (land), marine (sea), and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.

In simpler terms, Biodiversity is all the living creatures, plants and animals, on and in the earth, water and air in a particular place. Biodiversity also describes the interaction between these living creatures and the area (ecosystem) in which they live.

Why Is Biodiversity Important?

Biodiversity supports human life and livelihoods in that it provides a number of ‘ecosystem services’:

  • is a source of food, medicine, fuel, grazing for livestock, and building materials
  • contributes to food supply, for example the pollination of commercially viable crops, such as citrus, grapes and apples; the continued productivity of soils, and the control of pests and diseases
  • is essential for the regulation or control of natural processes that support human life, for example, soil formation, reduction of carbon that contributes to global warming (the potential increase in the temperature of the earth’s atmosphere caused by pollution), recycling of nutrients, and the supply and purification of water
  • it helps to regulate floods and protects against storm surges
  • provides space for leisure and tourism
  • has social, health and spritual benefits for humans, and contributes to their quality of life

How Is Biodiversity Affected By Development?

  • Habitat loss and degradation, for example, the destruction of wetlands, grasslands and indigenous forests for housing estates or low cost housing.
  • Habitat fragmentation – ecosystems and the species therein, need a certain amount of interconnectivity for processes to continue. If a specific natural area is broken up into smaller pieces, eventually species disappear and certain functions are lost. For example, a large intact wetland can fulfill its functions far better than a wetland that is divided into two pieces.
  • Loss of species, for example the plants and animals endemic to a particular habitat will not be able to survive if that habitat is destroyed or altered by development.
  • Natural environmental processes, such as continued river flow, water purification, and erosion control, are affected. This can lead to an accumulated effect on both habitat and species. Or, this can continue to affect habitats and therefore species into the long-term until they die out.
  • Direct impacts, for example birds colliding with power lines, electrocutions.
  • Alien invasive organisms that can transform natural habitats.
  • Pollution effects on ecosystems and thus species.

How To Consider Biodiversity In The EIA Process

Typically what happens (or should happen) during the EIA process is that the impacts on Biodiversity are investigated by a specialist – people with the correct qualifications in botany, ecology, entomology etc. usually at a postgraduate level. Specialists who can focus broadly on the impacts across the ecosystem should be brought in early. These specialists will not focus merely on fish for example, but more generally on the entire freshwater ecosystem, or not merely on mammals but on the entire terrestrial ecosystem. Later, once the general impacts are identified, specialists on fish, botany (plants), mammals, birds, geology etc could be involved where relevant. The specialist could be an ecologist from the local conservation agency or a consultant. These specialist studies are usually conducted in the following fields of Biodiversity (depending on the type of development):

  • Botany Or Terrestrial Ecology Which could include a wetlands, grasslands, fynbos, forest or other habitat component
  • Freshwater Ecology Which could include a wetlands, riverine, grasslands or other habitat component
    Marine Or Estuarine Ecology Coastal, sea or estuarine habitats
  • Geology Soil erosion, suitability for development
  • Mammals
  • Birds
  • Amphibians
  • Reptiles Sometimes the last four are all grouped together under vertebrates (animals with a backbone)
  • Invertebrates – Animals without a backbone

The specialist has to look at how ecosystems and species could be affected by development, and how best the development can be designed, located and managed to avoid negative impacts or result in benefits to Biodiversity.

When assessing the likely significance of an activity, it is important to take the following into consideration:

In addition it is important to consider the impacts of the proposed activity/s on

  • Biodiversity pattern (this will be the structure and composition). The impacts on the Biodiversity pattern should be assessed at both species level as well as ecosystem level (ie. considering landscapes as well as development sites).
  • Biodiversity process (function). The impacts on the Biodiversity process should be assessed at both species level as well as ecosystem level.
  • Ecosystem services (as described above) and the associated effects on those people or communities, or society at large, who may depend on these services for their livelihoods or wellbeing.

It is not only essential to assess the impacts on the affected site, but also to consider the impacts beyond the site (in a regional and catchments context). In addition, it is important to think of both direct (eg. clearing of vegetation) as well as indirect impacts (eg downstream impacts of on-site changes in water flow) and cumulative (additive) impacts. For more detailed guidance on the above, please access the DEADP Guidelines and CBBIA Guidelines provided below.

Generally, the impacts are assessed by the specialists according to the following criteria drawn from the EIA Regulations, published by the Department of Environmental Affairs and Tourism (April 1998) in terms of the Environmental Conservation Act No. 73 of 1989. These criteria may change according to the specialist field. These criteria include:


Criteria Description of elements that are central to each issue
Nature of impact This is an appraisal/evaluation of the type of effect the construction, operation and maintenance of a development would have on the affected environment. This description should include what is to be affected and how.
Extent of the impact Describe whether the impact will be:
Site Specific
Extending only as far as the activity, or
Limited to the site and its immediate surroundings

Will have an impact on the region

A development can often have a regional impact on Biodiversity. If a feeding site for birds or mammals is destroyed, the population might leave the area or go extinct if they don’t find other suitable areas. The same applies for national and international if one considers the cumulative impacts. Studies have shown that housing developments can lead to losses of up to 90% of the species in an area where as stock farming on natural veld ensures that up to 80% of the species remain.

Will have an impact on a national scale – particularly if an ecosystem or species of national significance is affected
Will have an impact across international borders or will impact on an ecosystem or species of international significance

Duration of impact

Short Term
(0-5 years)
Medium Term
(5-15 years)
Long Term
(16-30 years)
Impact will cease after the operational or working life of the activity, either due to natural process or by human intervention
Impact will be where mitigation or moderation by natural process or by human intervention will not occur in such a way or in such a time span that the impact can be considered transient or temporary
Discontinuous Or Intermittent
Impact may only occur during specific climatic conditions or during a particular time of year

IntensityThe specialist should establish whether the impact is destructive or benign (mild) and should be qualified as:

Low Impact
Affects the environment in such a way that natural, cultural and soil functions and processes are not affected
Affected environment is altered by natural, cultural and soil functions and processes continue although in a modified way
Natural, cultural or social functions or processes are altered to the extent that they will temporarily or permanently cease
The specialist study must attempt to quantify (or measure the amount of) the extent of the impacts and outline the rationale or reasoning used.

Probability of occurrenceThe probability of the impact actually occurring and should be described as:

Low likelihood
Distinct possibility
Highly Probable
Most likely
Impact will occur regardless of any prevention measures

Determination of significanceBased on a synthesis or combination of the information contained in the above-described procedure; and drawing on standards, targets for Biodiversity conservation, known thresholds for ecosystem services, species or ecosystem viability, and/or carrying capacity of ecosystems; the specialist is required to assess the potential impacts in terms of the following significance criteria:

No Significance
The impacts do not influence the proposed development and/or environment in any way
Low Significance
The impacts will have a minor influence on the proposed development and/or environment. These impacts require some attention to modification of the project design where possible, or alternative mitigation (a choice of other methods to alleviate the impacts)
Medium Significance
The impacts will have a moderate influence on the proposed development and/or environment. The impact can be ameliorated (lessened or improved) by a modification in the project design or implementation of effective mitigation measures. Should have an influence on decision, unless it is mitigated
High Significance
The impacts will have a major influence on the proposed development and/or environment. The impacts could have the no-go implication on portions of the development regardless of any mitigation measures that could be implemented. Influence decision, regardless of any possible mitigation

ConfidenceThe specialist should state what degree of confidence there is in the predictions based on the available information and level of knowledge and expertise.


The Impacts Should Also Be Assessed In Terms Of The Following Aspects:

  1. Legal Requirements

    The specialist should identify and list the relevant South African legislation and permit requirements relevant to the development proposals. He / she should provide reference to the procedures required to obtain permits and describe whether the development proposals contravene or oppose the applicable legislation.

  2. Status Of The Impact

    The specialist should determine whether the impacts are negative, positive or neutral (this is a cost – benefit analysis). The impacts are to be assessed in terms of their effect on the project and the environment. For example, an impact that is positive for the proposed development may be negative for the environment. It is important that this distinction is made in the analysis.

  3. Risk Or Likelihood Of Irreversible Or Irreplaceable Loss Of Natural Capital

    The specialist should state clearly whether or not the impacts may be irreversible, or may result in an irreplaceable loss of Biodiversity (e.g. loss of a population, species, special habitat, threatened ecosystem). The specialist should also state the levels of uncertainty associated with making predictions of impacts.

  4. Effects On Valued Ecosystem Services

    The specialist should state clearly whether or not the impacts could result in either a degradation or deterioration of ecosystem services, and the associated implications to affected communities or society as a whole should be explained.


  1. BSSACU – Recommended Terms Of Reference For The Consideration Of Biodiversity In Environmental Assessment And Decision-making   38KB
  2. IAIA – Biodiversity In Impact Assessment   94KB
  3. CBBIA Guidance Document on Biodiversity, Impact Assessment and Decision Making in Southern Africa   3.1MB
  4. CBD – Voluntary Guidelines On Biodiversity, including Impact Assessment   168KB
  5. DEADP Guideline For Involving Biodiversity Specialists In EIA Processes   904KB